Abstract: | Regeneration of the nicotinamide cofactor is a critical issue in biocatalysis. Herein we have screened xanthene dyes for a highly efficient, visible light‐driven photochemical regeneration of cofactors and enzymatic synthesis. Superior catalytic performance was observed with several xanthene dyes such as phloxine B, erythrosine B, eosin Y, and rose bengal. We found that the photo‐ and electrochemical properties of the xanthene dyes were affected by the halogen atom substitution, which is a key factor in the efficient light‐induced electron transfer from the donor molecule to the catalytic mediator. |